The most common forming machines are paper or board machines. Along with the increasing speeds of the paper and board machines, traditional roll-based coating methods and coating equipment have reached the limit of usability. Even at the present speeds coating materials tend to splash off the roll surface. In addition, vibration of elements used in applying and/or smoothing the coating material, such as doctor blades, is a problem. Coating of a thin web is also problematic mainly due to an insufficient strength. Furthermore, the rolls are large and the coating station therefore requires a lot of mounting space.
To eliminate the above mentioned and other problems, so-called non-contacting applicator elements have been developed for the coating stations. In the practical use, these developed coating stations use several nozzles for spraying the coating material onto the web surface. This is also referred to as atomizing of coating material. Embodiments of this type of coating station are set forth for example in the European patent No. 0826085. This patent teaches a method in which coating material, which is most commonly coating paste, is sprayed onto the supported web surface using nozzles connected to a supply pipe. The nozzles are additionally adapted in groups, which are located in a specific box for collecting the excess coating material spray. The patent also teaches that the coating unit must be provided with a sufficiently rigid frame. However, no more detailed description of the frame is given.
In traditional coating stations, like in the developed ones, the frame has heretofore customarily been formed of beam-like construction steels by welding. This kind of frame is massive and heavy, the coating station thus becoming large and unwieldy. At the same time, only reduced freedom remains for the positioning of the coating station. Besides the beam construction, the coating station-comprises various pipeworks, which further increase the total weight of the coating station. In addition, the previously mentioned European patent requires a specific box, which defines a large area. This increases the consumption of the coating material and complicates cleaning in particular when changing the coating material. Cleaning and maintenance of the nozzles located inside the box is also cumbersome.